Lubrication of percussive tools



' 35 improper lu Patented May 24, 1927.

UNITED STATES PATENT OFFICE.

TOOL COMPANY, OF NEW YORK,

N. Y., A CORPORATION OF NEW JERSEY LUIBBIOATION OF PERCUBSIVE TOOLS.

Application fled November 13,1923. Serial No. 874,448.

This invention relates to improvements in percussive tools andparticularly concerns the automatic application of lubricant to theworking parts. In tools of this character,

the matter of lubrication is of great importance due to the high speedat which such tools operate and the power developed thereby which issooirdiverted from useful work to destructive heating and rapid wear ofparts when internal friction develops.

Heretofore the method of lubrication generally employed has beengravity'feed, frequently combined in the case of flui pressure operatedtools with eduction o lubricant caused by the passin of the motive fluidacross or past the ln ricant opening. In either case, during theoperation of the tool, air under pressure works into the lubricantchamber augmenting the flow of lubricant and continuing to expel thesame even after the operation of the tool ceases. This results in anexcess of lubricant on the working parts which is not only wasteful butinterferes with the roper functioning of 2 the tool. Moreover, t eresulting quick emptying of the lubricant chamber necessitates frequentinspection and attention to prevent the tool from being operated in adry condition by a careless or indifierent workman until it jams orbreaks down entirely. In view of the abuse to which tools of thischaracter are frequently that much of their unsatisfactory operation andhigh re air cost is directly traceable to rication.

mong the objects of the invention are to provide a lubricating systemfor tools of the character described whichshall distribute the 'oil orother lubricant automatically while the tool isin operation, which shafunction properly regardless of the angle at which the tool issupported, and in general to produce an eilicient and posit1ve' is.

.tribution of the lubricant and to avoid the defects of previoussystems. v

In brief the invention comprises an automatic lubricating system forpercussive tools 5 in accordance with requirements and only p 21 k d t heeve eye 0 o no subjected, it follows by the block or ron't head.Extension {of the piston is im .the form shown,

usual rifle bar-mechanism com rising rifle "bar 22 rotatively mounted inadapted to operate in synchronism wi h the reciprocations of thepercussive member to force lubricant against gravity to the workingparts. In order to illustrate the invention, one embodiment thereof isshown in the accompanying drawings, in which:

Fig. 1 is a. vertical longitudinal sectional view;

Fig. 2 is a fragmentary sectional view similar to Fig. 1, showing theimpact piston in a different position;

Fig. 3 is a transverse sectional view on the line 3-3 of Fig. 1' andFig. 4 is a top plan view of the cylinder 'l he embodiment of theinvention chosen for the purpose of illustration comprises a percussiverock drill of the pneumatic type aving a cylinder 5 provided with afront head 6 and a rear head 7 held in assembled relation in the usualmanner as by side or through bolts 8 (Fig. 3). Within the piston chamber9 of cylinder 5 the impact mem-' her or piston 10 reciprocates under theimpulse of live air which enters the tool at 11 (Fig. 3 under thecontrol of a hand throttle 12' y which it is admitted to a passage 13(Fig. 1) which leads to an automatic distributing valve (not shown)mounted in a lateral extension 14 of cylinder 5 and arranged to admitthe live motive fluid to the piston chamber alternately above and belowpiston 10 through ports 15 and 16 respectively. An extension 17 orpiston -10 guided uide sleeve 18 reciprocates in the front head 6 andimparts blows to a working tool or drill bit 19 removably suported 1nchuck20 rotatively mounted in t e 17 has vertical ribs grooves in arotative 20 whereby rotation arted to the drill bit. In episton isrotated by the 17 cooperating with earings n the back head 7 andcylinder ring 23 and cooperating with a rifle nut 24 secured in thecentral bore 25 of the piston, the bar having thereon a pawl carrier 26which fits in a chamber in the back head and has pawls arranged forcooperation with a ratchet ring 27 in the head.

By reason of the high speed at which a percussive tool of this typeoperates, frequent and adequate lubrication IS a necessity to preventrapid wear. In the present instance such lubrication is efl'ectedautomatically by the system now to be described. The chamber orreservoir for oil or other fluid lubricant may be in any suitable ordesired position in the tool, provided that the outlet thereof is abovethe reservoir so that the lubricant must be forced against gravity. Inthe present instance the 011 reservoir 28is positioned in the guidesleeve 18 or between it and the cylinder wall. the same being arrangedto be filled with oil 29 through an openin closed by a plug 30.

A passage 30' leads rom the reservoir upward through the wall of thecylinder 5 and is adapted to connect with a similar passage 31 in theback head 7 which passage has a cross port opening into an annulargroove 32 in the rear of the head so that lubrlcant issuing from thepassage is sprayed upon the parts of the rotation mechanism in thechamber of back head 7. This chamber is in communication with the pistonchamber by a groove 33 in the cylinder ring 23 whereby the lubricant hasaccess to the ribs of the rifle bar and to the walls of the pistonchamber, this groove bein intermittently covered and uncovered by t eblades of thepipiwl carrier as the latter rotates when the 3 Thence 11is in operation (see t y gravi y,

the lubricant works downwar assisted by the variations in uid pressurein the piston chamber, along extension 17 of the piston and into thefront head, a

roove 34 in the front head 6 or chuck 20 oing provided, if necessary, topermit access of the lubricant to the bearing surfaces of these parts.At some oint in the connecting passage between t e reservoir and thepiston chamber, the size of the passage is restricted, the amount ofsuch restriction determinin the flow of lubricant. While thisrestriction may be made in the passage at any suitable point and in anydesired manner, for convenience and by preference, the same is efl'ectedby a perforated plu 35 inserted in the bore 30 at the rear en ofcylinder 5.

The 0 eration of the lubricating system is as fol ows: When the tool isin operation, the air pressure in the rear of the iston chamber variesdue to the reci rocation of the impact member 10 and to t e alternateadmision and exhaust of fluid pressure throu h the intake port 15 andexhaust port 6, respectively. The lubricant 29 in the reservoir 28 issubjected to these pressure variations through the connecting pas- 5 sae which comprises groove 33 in the cylinier ring 23, the chamber in backhead 7, the annular groove 32 and bore 31 therein, the restricted oening in plu 35 and bore 30' in the cylinder 5. Thus, w ion the piston10 has moved rearwardly beyond the exhaust port 36, and during itsforward stroke (Fig. 2) under the thrust of live fluid entering at 15,pressure fluid works into the connecting passage to the reservoir inlimited amount through the restricted opening in plug 35. This pressurefluid at first mixing with the lubricant eventually separates out and istrapped in the upper part of the reservoir, as indicated by the spacetherein shown in Figs. 1 and 2, thus placing the lubricant in thereservoir under ressure. When the piston on its forwar stroke passesbeyond the exhaust port 36, to the position shown in -Fig. 1, animmediate rop in pressure in the upper end of the piston chamber takesplace, resulting in a spurt of lubricant from the passage 3031 into thechamber in the back head? and upon the working parts therein, whence thelubricant works down through the tool in the manner above described, therotation of the working parts serving to distribute the lubricant evenlyand throwing a portion of it out against the walls of the cylinder 5 andfront head 6, the amount of lubricant in each spurt bein determined bythe size of the opening in the plug 35. Thus .it will be evident thatthe lubricant is forced against gravity and is then distributed evenlyand in accordance with the requirements of the tool, the feed of thelubricant being intermittent, in synchronism'with the movement of theimpact member, and ceasshortly after the stopping of the tool. ile theinvention has been disclosed as embodied in a pneumatic hammer drill, itis to be understood that the invention is not so limited but is capableof use with pneumatic tools generally and with percussive tools notactuated b motive fluid. In applying the system to iiferent tools, theposition'of the lubricant reservoir may vary as well as the point of,connection of the passage thereto in order that when the tool is held inany of its normal working positions the flow of lubricant to the workingparts will be against gravity.

\ claim:

1. In a percussive tool having a piston chamber and an impact pistonreci rocable therein, a chamber in line with sai piston chamber andconnected thereto, a lubricant chamber disposed below said second namedchamber in the normal position of the tool, and a continuously openpassage leading from said lubricant chamber to said second named chamberwhereby the lubricant is subjected to the varyi n pressure within saidpiston chamber and is Forced against-gravity through said passage intosaid second named chamber.

2. In a percussive tool'having a'piston chamber and an impact pistonreci rocable therein, a chamber in line with sai piston chamber, meansintermittently connecting said chambers when the tool is in operation, alubricant chamber disposed below said-second named chamber in the normalposition of the tool, and a continuously open passage leading from saidlubricant chamber to said second named chamber whereby the lubricant issubjected to the varying pressure within said piston chamber and isforced against gravity through said passage into said second namedchamber.

i 3. In a percussive tool having a piston chamber and an impact pistonreciprocable therein, a chamber in line with said piston chamber andconnected thereto, a lubricant chamber disposed below said second namedchamber in the normal position of the tool, a continuously open passageleading from said lubricant chamber to said second named chamber wherebythe lubricant is subjected to the varying pressure within said pistonchamber. and is forced against gravity through said passage into saidsecond named chamber, and means for restricting the flow of fluidthrough said passage.

4. In a percussive tool having a piston chamber and an impact pistonreciprocable therein, a chamber in line with said'piston chamber, meansintermittently establishing communication between said chambers, alubricant chamber so disposed as to be beneath said second named chamberinthe normal position of the tool, a continuously open passage leadingfrom said lubricant chamber to said second named chamber, and means forrestricting the flow of fluid -through said passage.

5. In a percussive tool having a piston chamber and an impact pistonreciprocable therein, a chamber rearwardly of said piston chamber,rotation mechanism in said second named chamber, a perforated separatingmember providing restricted communication between said chambers, alubricant chamber, a continuously open passage leading from saidlubricant chamber to said second named chamber for subjecting thelubricant to the fluctuating pressure in sai'd 'fiston chamber and forconducting lubrican to said mech a iinism.

6. IIl-a QQFPQXCllSSl-YB tool having a piston chamber and an impactpiston reciprocable therein, a chamber rearwardly of said pis tonchamber, rotation mechanism in said second named chamber, a separatingmember between said chambers providing a connection therebetween undercontrol of said mechanism, a lubricant chamber, acontinuously openpassage leading from said lubricant chamber to said second named chamberfor subjecting the lubricant to the fluctuating pressure in said pistonchamber and for conducting lubricant to said mechanisnr.

7. In a percussive tool having a piston chamber and an impact pistonreciprocable therein, a chamber rearwardly of said piston chamber,rotation mechanism in said second named chamber, a separating memberbetween said chambers providing a connection thcrebetu'een under controlof said mechanism, a lubricant chamber, a continuously open passageleading from said lubricant chamber to said second named chamber forsubjecting the lubricant to the fluctuating pressure in said pistonchamber and for conducting lubricant to said mechanism, and means at onepoint in said assage for restricting the flow of fluid t erethroughthereby to create a time lag in the effect of the pulsations of pressureupon the lubricant.

8. A pneumatic hammer drill having a cylinder, front and back heads atthe ends thereof, a working tool in said front head, a hammer pistonreciprocable within said cylinder, a mechanism for rotatin said tool,and means for lubricating the wor ing parts comprising a lubricantreservoir closed save for a sin le passage terminating above thelubricantdevel and arranged for communcation with the interior ofsaidcylinder whereby the varying pressure in the piston chamber forces thelubrication against gravity through said passage in synchronism with themovement of said piston.

9. A pneumatic hammer drill having a cylinder, a cylinder rin and a backhead closin one end thereo a front head for the ot er end, a rotatablechuck for a working tool in said front head, a hammer pistonreciprocable within said cylinder and keyed to said chuck, rifle barrotation mechanism mountedin said back head for coaction with saidpiston, and means for lubricating the moving parts in synehronism withthe reciprocation of said piston comprising a lubricant reservoiradjacent said front head a passage leading from said reservoir to saidback head and terminating adjacent said roation mechanism, and a recessin said cylinder ring intermittently opened and closed -by saidmechanism for establishing comnunication between the piston chamber andsaid passage thereby to subject the lubricant to the varying-pressure insaid chamber.

10. A rock drill of the percussive type com rising a cylinder havingfront and back hea s, a working tool rotatably mounted in the fronthead, a hammer piston reciprocable within the cylinder to deliver blowsupon the working tool, mechanism for imparting rotation to the workintool, a lubricant whereby the lubricant is subjected to the reservoiradjacent said ront head, a passage varying pressure behind said piston,and a leading rearwardly from said reservoir and plug in said passagefor limiting the flow terminating adjacent said mechanism, meanstherethrough to a predetermined amount. under control of said mechanismfor estab- Signed by me at Detroit, Mich., this 6th lishin communicationbetween said passage day of November, 1923.

and 5m proximate end of the cylinder 7 ERNEST PEN BERTHY.

rotation to the workin tool, a lubricant whereby the lubricant issubjected to the reservoir adjacent said front head, a passage varyingpressure behind said piston, and a leading rearwardly from saidreservoir and plug in said passage for limiting the flow terminatingadjacent said mechanism, means therethrough to a predetermined amount.under control of said mechanism for estab- Signed by me at Detroit,Mich., this 6th lishing communication between said passage day ofNovember, 1923.

and the proximate end of the cylinder ERNEST PENBERTHY.

CERTIFICATE or CORRECTION.

Patent No. 1,629., 730i Granted May 24, 1927. to

cancer PENBERTHY.

It is hereby certified that error'appears in the printed specificationof the above numbered patent requiring correction as follows: Page 3,strjlte out lines 90 to 102, comprising claim 8 and insert instead thefollowing as claim 8. "8. A pneumatic hammer drill having a cylinder,front and back heads at the ends thereof, a working tool in said fronthead, a hammer piston reciprocable within said cylinder, mechanismassociated with said piston for imparting rotation to said tool, andmeans for lubricating the moving parts comprising a lubricant reservoiradjacent said front head and closed save for a single restricted passageterminating adjacent said mechanism, andmesns under control of saidmechanism for establishing communication between said passage and thepiston chamber, whereby the varying pressure in the piston chamberforces the lubricant against gravity through said passage in synchronism with the movement of said piston. and that the said Letters Patentshould be read with this correction therein that the same may conform tothe record of the case in-the Patent Office.

Signed and sealed this 27th day of September, A. D. 1927.

w M. J. Moore.

Seal. Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No 1.629; 730 Granted May 24. 1927. to

ERNEST PENBERTHYt It is thereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Page 3, strike out lines 90 to 102, comprising claim 8 andinsert instead the following as claim 8, "8. A pneumatic hammer drillhaving a cylinder, front and back heads at the ends thereof, a workingtool in said front head, a hammer piston reciprocable within saidcylinder, mechanism associated with said piston for imparting rotationto said tool, and means for lubricating the moving parts comprising alubricant reservoir adjacent said front head and closed save for asingle restricted passage terminating adjacent said mechanism, andtneansunder control of said mechanism for establishing communication betweensaid passage and the piston chamber, whereby the varying pressure in thepiston chamber forces the lubricant against gravity through said passagein synchroniam with the movement of said piston. and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case inthe Patent Office.

Signed and sealed this 27th day of September, A. D. 1927.

M. J. Moore,

- Seal. Acting Commissioner of Patents.

